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Ruxolitinib, nilotinib and prednisone for myelofibrosis
unmet clinical need to increase the effectiveness of the treatment and decrease its toxicity guides the search for combination treatments with ruxolitinib.
The main objective of this work was to evaluate the best combination of drugs for the treatment of MF, main- taining ruxolitinib as a therapeutic base and reducing its toxicity while maintaining its efficacy. Since MF is not characterized by large amounts of pathological cells, as in acute myeloid leukemia,27 it is challenging to develop
an ex vivo model to screen 17 combinations. Consequently, we elected to utilize myeloid cells obtained from 14-day old cultures of PBMCs in methyl- cellulose (ex vivo model B), which produce a sufficient supply of cells for screening. Interestingly, the most active drugs in monotherapy coincided with the most active drugs in preclinical trials, including bortezomib,28 panobinostat29 and HSP990.30 Therefore, the search for combination treatments with ruxolitinib is in response to
A
B
Figure 3. Effect of 32 nM ruxolitinib (R), 1.6 μM nilotinib (N), 0.8 mM prednisone (P), and their combinations, on the phosphorylation of ERK1/2 and STAT5 in cell lines. Results are expressed as the mean±Standard Error of Mean. Data are representative of at least 2 separate experiments. *P<0.05; **P<0.01; ***P<0.001. C: control.
Table 4. Combination Index (CI) of ruxolitinib (R), nilotinib (N) and prednisone (P) in samples of myelofibrosis (MF) patients and healthy donors. Mononuclear cells from peripheral blood of MF patients and healthy donors were seeded at 200,000-500,000 cell/mL in Metocult supplement- ed with SCF and IL3 in presence of drugs for two weeks. Then flow cytometry analysis was performed.
Drugs MF
Healthy donors
C1 C3
0.24 0.20
0.12 0.13 0.30 >2 0.21 0.13 >2 >2 0.53 >2 0.48 >2 0.54 >2
Nilotinib (mM) 1.6
8 1.6 8
32 1.6 4 >2 >2 0.15
160 8 0.8 0.31 0.64 0.20
160 8 4 0.39 >2 0.13
CI < 0.9 indicates sinergy (Italic); CI > n 1.1 indicates antagonism (Italic Bold). P<0.05 is considered significative.
Prednisone (mM)
32 1.6 0.8 >2 >2 0.36
Ruxolitinib (nM)
32
32 160 160
P20 P33 P27
P19 P34
0.40 0.22
>2 0.50 1.09 1.44 0.18 0.30 1.83 1.05 0.32 1.55 0.4 0.22
0.34 0.55 0.20 0.16 0.20 0.05 0.43 0.10 0.24 - 0.10 0.02
0.18 -
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